fix(http): fixed support for IPv6 literal strings in url (#5731)

lib/adapters/http.js

@@ -427,7 +427,7 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
     if (config.socketPath) {
       options.socketPath = config.socketPath;
     } else {
-      options.hostname = parsed.hostname;
+      options.hostname = parsed.hostname.startsWith("[") ? parsed.hostname.slice(1, -1) : parsed.hostname;
       options.port = parsed.port;
       setProxy(options, config.proxy, protocol + '//' + parsed.hostname + (parsed.port ? ':' + parsed.port : '') + options.path);
     }

test/unit/adapters/http.js

@@ -159,6 +159,44 @@ describe('supports http with nodejs', function () {
     delete process.env.no_proxy;
   });
 
+  it('should support IPv4 literal strings', function (done) {
+
+    var data = {
+      firstName: 'Fred',
+      lastName: 'Flintstone',
+      emailAddr: 'fred@example.com'
+    };
+
+    server = http.createServer(function (req, res) {
+      res.setHeader('Content-Type', 'application/json');
+      res.end(JSON.stringify(data));
+    }).listen(4444, function () {
+      axios.get('http://127.0.0.1:4444/').then(function (res) {
+        assert.deepEqual(res.data, data);
+        done();
+      }).catch(done);
+    });
+  });
+
+  it('should support IPv6 literal strings', function (done) {
+
+    var data = {
+      firstName: 'Fred',
+      lastName: 'Flintstone',
+      emailAddr: 'fred@example.com'
+    };
+
+    server = http.createServer(function (req, res) {
+      res.setHeader('Content-Type', 'application/json');
+      res.end(JSON.stringify(data));
+    }).listen(4444, function () {
+      axios.get('http://[::1]:4444/').then(function (res) {
+        assert.deepEqual(res.data, data);
+        done();
+      }).catch(done);
+    });
+  });
+
   it('should throw an error if the timeout property is not parsable as a number', function (done) {
 
     server = http.createServer(function (req, res) {